Abstract
We present a density functional study of H2 adsorption on and desorption from Si(100)2×1 monohydride and Si(100)1×1 dihydride surfaces, carried out using a slab geometry with large supercells. For the monohydride surface we find that two distinct mechanisms - i.e. the recombination of two H atoms sitting either on the same dimer or on adjacent dimers along a row - yield desorption barriers in agreement with experiment. For the dihydride surface, the preferred pathway involves the desorption of two H atoms belonging to the same SiH2 unit. This is followed by a local structural rearrangement, leading to the formation of a surface dimer, and making the overall reaction slightly exothermic. The corresponding adsorption barrier, ≈ 2 eV, is large with respect to that inferred from desorption experiments.
Original language | English (US) |
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Pages (from-to) | 334-340 |
Number of pages | 7 |
Journal | Chemical Physics Letters |
Volume | 235 |
Issue number | 3-4 |
DOIs | |
State | Published - Mar 24 1995 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry